Ear stopper



June 24, 1941. v, of KNUDSEN 2,246,736

EAR STOPPER Filed Aug. 13, 1938 Patented June v24, 1941 UNITED STATESPATENT OFFICE EAR sTorPER l Vern O. Knudsen, Los Angeles, Calif.

12 Claims.

rIdhis invention relates to ear stoppers and relates more particularlyto ear protectors or ear stoppers for use by those who are disturbed bynoises and undesirable sounds, by those who are subjected toA thedetonations and excessive air disturbances of gun fire, riveting,blasting, etc., and by swimmers or others who wish to keep water orother undesirable substancesv from entering the ear canal.

Anotherl object of this invention is to provide ear stoppers embodyingcombinations or series of acoustical elements related and designated toprovide a substantial sound transmission loss or insulation throughout awide range of audible frequencies. Irl accordance with my invention thenetworks or series of acoustical elements of the stoppers may be sochosen and related as to Application August 1a, 193s, serial No. 224,759

(Cl. 12B-152) 4 is a reduced longitudinal sectional view of stillprovide a sound transmission loss or sound insulation characteristiccomparable with that provided by the temporal bone and vother anatomicalstructures that surround and-embed the human internal ear or cochlea.

Another object of this invention is to provide ear stoppers that embodyseries of acoustical elements or impedances coupled by other acousticalimpedances to constitute acoustical networks or combinations thatprovide the required or desired ratio between the transmitted and theincident sound energy throughout a given frequency range.

Another object of this invention is to provide ear protectors or earstoppers of the character mentioned that embody series or pluralities ofacoustical impedances in the nature of mass or inertia elements coupledby compliance type impedance elements in the form of loose couplingsbetween the mass impedances which transmit -a minimum oi sound energybetween the mass impedances.

Another object of this invention is to provide ear stoppers of thecharacter mentioned inwhich the mass impedances are in the form of partsof similar or dissimilar materials having different sound transmissioncoeiilcients,l and the compliance impedances are in the nature ofyielding walls or separators enclosing or defining spaces,

voids Aor gas chambers between the mass impedances.

Another object of this invention is to provide ear stoppers oi' thecharacter mentioned that are` simple and inexpensive to manufacture.

A further object of this invention is to provide `ear stoppers of thecharacter referred to that are another form of the invention.

In the following detailed description I will describe three typicalpreferred forms of the invention. It is to be understood that theinvention may be varied considerably without departing from its broaderprinciples and the invention is not to be construed as limited orrestricted to the specific forms about to be described.

The` ear stopper of the present invention illustrated in Figs. 1 and 2of the drawing may be said to comprise, generally, a yielding body I0for` insertion in the auditory canal C, a plug Il in the `outer portionof the body I0 constituting an impedance of. the mass type and a plug ormass I2 in the inner portion of the body I0 forming a second massimpedance spaced from the plug Il.

The body I0 of the device or stopper is designed to be inserted inthemeatus or auditory canal C of the human ear. The body Il)I is anelongate tubular or hollow member preferably of suiilcient diameter tosnugly ilt the canal C. In ac- Y cordance with the invention the body I0is formed of a iiexible, yielding and resilient material such as rubber,rubber composition, rubber substitute; or the like. The outer end of thebody I0 is open to receive the plug I I and the inner end of the bodyIII may be closed, as

illustrated in the drawing. It `is preferred to make the inner end ofthe body I0 round or convex in external configuration to facilitate theintroduction of the stopper to the auditory canal C.- In theconstruction illustrated the body III -has a partiallysphericalenlargement I3 on its sirable to provide the best possible t inthe ear canal.

The plug I I constitutes the iirstor outer inertia mass acousticalimpedance element of the device, being located in the outer portion ofthe body I to receive the incident sound energy.A The plug II ispreferably a solid or non-hollow member of brass, stainless steel; lead,bronze or similar metal or material of relatively high specific gravity.In practice the plug II may be tapered as shown to impart a similartaper to the body I0. The major portion of the plug II is inserted inthe outer part of the body IIJ and is suitably secured in the body. Theplug II may be cemented, vulcanized or otherwise xed in the stopper bodyI0. The plug II may extend outwardly beyond the end of the body I0, orit may be partially or completely surrounded by the body I0 in such amanner as to add to the comfort of wearing the device and to facilitatethe insertion and removal of the stopper. -In the particular embodimentof the invention shown in Figs. 1 and 2 the projecting portion of theplug I I is enlarged in diameter and is shaped to constitute a handle orknob It that may be conveniently engaged for the purpose of insertingthe stopper in the auditory canal C and for the purpose of withdrawingthe stopper from the ear. If desired or believed necessary the knob 'I6may be covered with a skin or coating I of rubber, or the like, or asshown in Fig. 3, the wall of the body III may diverge or flare outwardlyand partially surround the knob I l and thus prevent the plug II fromtouching the ear. Such diverging wall or flange may also improve theiitl of the stopper in the ear .cana'l and may also facilitate easyremoval of the stop per. spaced a considerable distance from the innerenlargementI I3 of the stopper body IU, but limitation of space in theear canal may require a short distance.

The plug or mass I2 constitutes the second or inner mass or inertia typeof acoustical impedance of the stopper. The mass I2 is provided in theinner part of the body Iii and in the structure illustrated occupies thehollow enlargement I3 of the body. The shape and proportions of the massI2 may be such that the mass distends the yielding resilient body Ill toprovide and maintain the enlargement I3, or if desired the bodyenlargement I3 may be preshaped or preformed to receive the mass I2, orthe mass I2 may be cast or formed of the same material as is used forthe body Ill in such shape as will best lt the ear canal. 'I'he partsmay be related and proportioned so that the inherent resiliency of thebody Ill holds the mass I2 in its proper position. If desired orbelieved necessary the mass I2 may be cemented, vulcanized or otherwisesecured in place the body I0. It is preferred to construct the mass I2of a yielding material such as soft rubber, sponge rubber, beeswax, orthe like, so that it will not cause injury to the ear when the stopperis inserted in the auditory canal C. Owing to the fact that the mass I2is of soft or yielding material its acoustical compliance and resistancemay be substantial although the mass I2 is primarily a mass impedance.

In accordance with the invention the mass I2 is spaced from the innerend of the plug I I to leave or provide a space or chamber I B in thebody I0. In practice the chamber I6 may be of substantial longitudinalextent as illustrated in the drawing. As will be evident the chamber I6is dened or enclosed by the surrounding wall The inner end of the plug II is preferably extending outwardly beyond the knob I 4a.

oi the body I and the opposing end surfaces of the plug II and the massI2. The chamber I6 may' contain air or other gas or, if desired, apartial vacuum may be maintained in the chamber I6. In the event thatthe chamber I6 contains a gas orsin the event that a partial vacuum ismaintained in the chamber the plug II is sealed in the body I8.

In the use or operation of the stopper illustrated in Figs. 1 and 2 ofthe drawing the stopper isinserted in the' auditory canal C to occupy aposition such as illustrated in Fig'. 1. If desired the body I0 may beprovided or covered with petroleum jelly, or the like, prior to theinsertion of the stopper so that the stopper may readily enter the canalC. 'I'he stopper maybe allowed to remain in the ear for as long a periodas required and may be removed when desired.

'I'he stopper is highly ecient in its sound insulation properties. 'Ihedense metal plug II forms the outer acoustical impedance or massimpedance of the device. The plug II, being of dense material, has asmall acceleration or displacement imparted to it by the force of theincident sound waves or explosion waves in the case of gun fire,blasting, etc. The mass I2 constitutes a second inertia or massacoustical impedance but being of soft material mayhave an appreciableacoustical compliance and resistance. The Wall of the yielding body I0and the chamber I6 between the plug II and the mass I2 constitute a veryloose coupling between the plug and mass I2. This loose coupling is ahighly eiclent acoustical compliance and resistance element and only asmall fraction of sound energy communie cated to the plug I I istransmitted by the said loose coupling to the mass I2. From the above itwill be apparent that the stopper of the invention shown in Figs. 1 and2 involves two mass impedances separated by `a-iiexible coupling. vByvariation of the mass and size of the plug II, the character of the gasin the chamber I6, the dimensions of the chamber I E, the thickness andcompliance of the wall of the body I 0 and the size, compliance anddensity of the mass I2, the sound transmission and insulatingcharacteristics of the device or stopper may be altered to suit variousconditions of use or application. 'Ihe stopper constructed as describedabove provides a transmission loss or sound insulation of betweenapproximately 45 to 60 decibels throughout a. wide range of audiblefrequencies.

The form of the invention illustrated in Fig. 3 of the drawing ischaracterized by an additional or third mass impedance. The improved earstopper of the invention illustrated in liigl 3 may be said to comprise,generally, a body Illa, a plug II a in the outer portion of the bodyIIIe, a mass I2a in the inner portion of the body IIIa and a partitionI8 in the body I0 spaced between the plug I Ia and the mass I2a.

The body Illa may be similar to or identical with the body I 0 describedabove and the plug I Ia may be similar to the plug I I. In theparticular case illustrated the plug I IP- is somewhat shorter than the.plug II and has a smaller knob Ita. The body I may have a ilaringflange or skirt 30 'I'he skirt` prevents contact of the knob |48 withthe luser, limits insertion of the stopper in the auditory canal,assures a better t of the stopper in the canal and facilitates theremoval of the stopper from the ear. The mass I2 is similar to the abovedescribed mass I2 and occupies the enlarged inner portion I3Si of thebody I0, The

mass I2* is preferably formed of soft or yielding material and isprovided with a central cavity I! to render it more yielding. The bodyIII, the plug IIa and the mass I2'l may be constructed of the samematerials as the body III, plug II and mass I2, respectively, of thepreviously described form of the invention. Furthermore,.

tween the opposing ends ofthe plug Il* and the mass I2* although theposition of the partition may be varied as found desirable. 'I'hepartition I8 may be constructed of any suitable material having asubstantial density. Any suitable means may be employed to retain thepartition I8 in the body IIIe'. In the typical arrangement illustratedthe edge or peripheral portion of the partition is gripped `or receivedin an internal groove 22 in the wall of the body I. If desired ornecessary The plug IIh is spaced some distance forwardly from the mass82h, providing achamber lib within the body I0. Any suitable means maybe employed to secure the plug I Ib in place. In the case illustratedthe peripheral portion of the plug IIb is received and secured in aninternal groove 22b in the body Illb.

Having described only typical preferred forms and applications of myinvention, I do not wish to be limited or restricted to the speciiicdetails herein set forth, but wish to reserve to myself any variationsor modifications that may appear to those skilled in the art, or whichfall within the scope of the following claims:

Having described my invention, I claim:

1.. An ear stopper of the character described comprising spaced solidmatter parts forming acoustical mass impedances, said parts beingofdiierent densities, and a yielding tubular body adapted to be receivedin the auditory canal whose end portions contain and are defined by thesolid matter parts, the body constituting l an acoustical compliancecoupling said parts.

the partition I8 may be cemented or vulcanized v in the groove 22.

The two chambers 20 and 2i in the body III'i may contain air or gas, ora partial vacuum may be maintained in the chambers. Cotton or wool fibreF, synthetic bre, or the like, is loosely arranged in the chambers 20and 2l to provide a better sound insulation.

The stopper of the invention illustrated in Fig. 3 may be employed inthe same manner as the previously described form of the invention. 'niestopper shown in Fig. 3 operates in substantially the same manner as thepreviously described form of the invention; however, it embodies a thirdmass acoustical impedance, namely, the partition I8. It will be seenthat the stopper of Fig. 3 embodies three inertia or mass impedancescoupled by loose couplings. The three mass impedances are found in theplug Il, the partition I8 and the mass I2a and the loose couplings arefound in the body wall and the chambers 20 and 2| between the spacedimpedances. The loose couplings between the series of spaced massimpedances transmit a minimum of the sound energy from one massimpedance to the other and the network or system constitutes a highlyefilcient sound insulation device. l

Fig. 4 of the drawing illustrates a form of the invention particularlyadapted for use by swimmers and others who wish to prevent the entranceof fluids to the ears. In this form of the invention the body Il)b is-longitudinally tapered and is provided at its outer end with a flaringflange or skirt b similar to the above described skirt 30. The body IIlb may be constructed of rubber, rubber composition, or the like, andis flexible and resilient. The inner acoustical impedance mass I2b isformed integral with the body I0". y may take the form of an internalenlargement in the inner portion of the stopper body I0. The outeracoustical impedance mass or plug I Ib is in the form of a separator orpartition extending transversely across the interior of the body I0".The plug I Ib may be constructed of any suitable material, for example,it may be formed oi' the same material as the above described mass II.

As shown in the drawing the mass I2b l 2. An ear stopper of thecharacter described comprising spaced solid matter parts formingacoustical mass impedances. one of said parts being of dense unyieldingmaterial and the other part being of less dense yielding material, and ahollow yielding body adapted to be received in the auditory canal andwhose end portions contain and are defined by said parts, the bodytogether with said parts defining a closed chamber, said body andch-amber constituting aloose compliance coupling between said parts.

'3. An ear stopper including .a series of spaced masses having diiferentsound transmission coeillcients constituting acoustical inertiaimpedances, and a yieldable tubular body extending between andconnecting said masses and constituting an acoustical complianceimpedance coupling, said masses and the body defining closedv chambersbetween the masses.

4. An ear stopper including a series of spaced masses having diiferentsound transmission coefficients constituting acoustical inertiaimpedances, and a tubular body of yielding material carrying andconnecting said masses and defining chambers between the masses, thebody and said chambers forming acoustical compliance impedance couplingsbetween the masses.

5. An ear stopper comprising an elongate hollow yieldable body adaptedto be inserted in the auditory canal, a yieldable solid matter massclosing the inner end of the body and a substantially unyielding solidmatter mass closing the outer end of the body and maintaining the shapeof the outer portion of the body, the last named mass being spaced fromthe yieldable mass to leave a closed chamber in the body.

6. An ear stopper comprising an elongate hollow body of yieldableresilient material, a plug of dense solid matter material confined inone end portion of the body by the resiliency of the body, and a mass ofsoft solid matter material confined in the other end portion of the bodyin spaced relation to said plug to leave a closed space in the body.

7. An ear stopper comprising a tubular yieldable body closed at itsinner end and adapted to be introduced into the auditory canal, a metalp lug in the outer portion of the body. and a soft mass in the innerportion of the body spaced from the plug, said plug and mass beingspaced apart to leave a closed chamber in the body.

8. An ear stopper comprising a tubular yield- 4 Y A able body closedatits inner end. 'and adapted to be introduced intothe auditory canal,a. mass in the inner portion of the body, and a mass sealed in the outerportion of the body, one of said masses being soft and the other beingof substantial density, said masses being spaced` they plug and mass toleave chambers in the bo l1. An ear stopper comprising a. tubularyieldable body to be inserted in the auditory canal, a dense plug in oneend of the body, a yieldable mass in the other end of the body, atransverse partition in the body spaced from the plug and mass to leavechambers in the body, and absorptive bre in said chambers.

l2. An ear stopper comprising a tubular yieldable body closed at itsinner end and adapted to be introduced into the auditory canal, a.iiaring skirt on the outer end of the bodya metal plug in the outerportion of the body, and a soft mass in the inner portion of the bodyspaced from the plug.

VERN O. KNUDSEN.

